I see in another post you are staying @ POR. For DTD restaurants take the boat from POR to DTD or the bus.
The easiest to remember, in general is grab a bus to a Park, walk over to the bus loading for the resort you want to eat @ and take it to that resort.
For restaurants @ the Poly (Ohana, Kona) GF (Narcoosies, V&A, Citricos, etc.) Contemporary (CG, Wave) take a bus from POR to MK. Walk towards the MK entrance but veer left and follow the resort monorail signs, hop on the monorail and get off @ the resort where you are dinning. For WL or Hoop dee doo (FW) take the boat in the same area, instead.
For Epcot area resorts take the bus @ POR to HS, head towards the entrance to HS, veer right to the boat launch then take the boat & get off @ the resort where you are dinning.
For AKL take the POR bus to a park, get off, then walk over to the bus going from that park to AKL and hop on.
These are not the only ways to do this, btw. You can always go to DTD and catch the bus to the resort you want to eat @ there - I've just had LONG waits @ DTD, so I avoid it as a transfer point.
If dinner runs late, you're tired and don't want to mess with buses/transferring, take a taxi.